Bloomfield Hills-based Pulte Homes has been identified as one of the "greenest" home builders in the country.

Calvert, a mutual fund company based in Maryland and Massachusetts, ranked the publicly traded home building companies in the United States. The rankings were determined by the builders' environmental and sustainable practices. The company ranked Pulte (NYSE: PHM) second overall and No. 1 in performance in four key areas of sustainable building: energy use, water use, building material use and land use.

"Our efforts in energy efficiency were specifically cited, as Pulte has built more Energy Star homes - more than 15,000 - than any other builder," said Melanie Hearsch, Pulte spokeswoman.

Though sustainable building is relatively new among large production home builders like Pulte, the report acknowledges that the company is on the right path toward energy efficiency and responsible building practices, she added.

In Michigan, Pulte homes also go through an energy sealing process to reduce air leakage.

According to the report, green practices can mean increased sales. Despite the slump in the overall housing market, green building is seeing annual growth of as much as 30 percent, according to Calvert. Home owners are willing to pay a premium - to the tune of $18,500 on average, according to McGraw Hill Constructions 2006 - for greener and cleaner homes.

Since the late 1990s, Pulte has been active in building energy efficient homes, Jim Petersen, director of research and development for Pulte, said.

"How much of it varies by market," Petersen said. "Different markets have different challenges, and our solutions for those markets vary."

The southwest and west, he said, have been ahead of the rest of the country because they have unique water and energy supply issues, Petersen said.

Whether sustainable building translates to sales is not easy to determine.

"Based on limited sample size and this difficult market now, the dynamics would make it difficult for us to draw conclusions," Petersen said.

But market to market, he does believe that sustainable building can be important in Pulte's marketing strategy.

"It has to do with where that house is positioned. The research indicates that while almost everyone says they're green, but when it comes time to open their checkbook and pay for it, those who are willing to do it are generally more educated, in their 30s and 40s, with disposable income to pay for it," Petersen said.

Pulte has focused heavily on the energy side of sustainable building.

"That's what consumers connect with because they feel it most in their pocket. There is a powerful monthly reminder of how green their house really is," he said.